<!DOCTYPE html>
<html>
<head>
<style>
html { view-transition-name: unset }
#target {
  height: 100000px;
  width: 1000px;
  position: absolute;
  background: lightblue;
  contain: layout;
  view-transition-name: target;
}
.left {
  left: 8px;
}
.right {
  right: 8px;
}
::view-transition-group(*) {
  animation-duration: 0s;
}
</style>
<script src="../resources/runner.js"></script>
<script>
function startTest() {
  var transition;
  PerfTestRunner.measureFrameTime({
      description: "Measures performance starting/finishing a transition with a large element",
      setup: () => {
        transition = document.startViewTransition(() => {
          target.classList.toggle("left");
          target.classList.toggle("right");
        });
      },
      run: async () => { await transition.finished },
      done: () => {}
  });
}
</script>
</head>
<body onload="startTest()">
<div id=target class=left>This is a div!</div>
<div id="log"></div>
</body></html>
